This renewal proposal seeks continuing support for the NIH/CU Molecular Biophysics Predoctoral Training Program at the University of Colorado, Boulder. The goal of this nine-year old program is to prepare exceptional, highly motivated biophysics students for productive research careers. The thirty- seven training faculty are an outstanding, internationally recognized group of investigators from four departments: Chemistry & Biochemistry; Molecular, Cellular & Developmental Biology; Chemical & Biological Engineering; and Physics. These faculty, together with their students, are using state-of-the- art biophysical methods to elucidate fundamental aspects of macromolecular structure, dynamics, mechanism, and function in systems ranging from single molecules to complex, multi-component assemblies. Many of these projects focus on questions of direct relevance to human health and disease. Molecular Biophysics is the most rapidly growing research field on the Boulder campus. Twenty of the thirty-seven training faculty have arrived in Boulder within the last ten years. An important driving force behind this growth is the NIH/CU Molecular Biophysics Training Program, jointly supported by NIH and University funds. The training program has established a thriving biophysical community with extensive collaborations among biophysicists in different laboratories and departments. Moreover, the program provides rigorous training for predoctoral students of biophysics, ensuring that such students receive the broad, interdisciplinary foundation needed to carry out cutting edge biophysical research. Required coursework includes biophysical courses developed specifically for the program and a Responsible Conduct of Research course. Training during the first year includes coursework, laboratory rotations, and teaching duties. Training during the second year includes additional coursework and defense of the planned thesis project in an oral PhD candidacy exam. Following the second year, students meet yearly with a faculty committee that provides independent feedback on their thesis research. In all training years, regular Biophysics Seminars and Super group meetings encourage strong communication and collaboration between biophysical students, faculty, and laboratories. During the current funding period, the training program has exhibited strong progress in multiple dimensions as evidenced by 1) addition of exciting new faculty, 2) recruitment of growing numbers of high quality, eligible students to the member departments, 3) increased participation by matriculates, 4) increased participation and graduation of underrepresented groups, 5) innovations in training, 6) strong publication, graduation, and postdoctoral entrance rates of trainees, and 7) large numbers of collaborative publications between training laboratories.